Hair drug testing: Many street drugs (or their breakdown products in the body) are absorbed into the hair. A sample of hair can be tested for recent drug use. Hair analysis: Testing of hair for toxic exposures, such as lead or mercury poisoning.
Gas Water Heater, water not hot enough-Thermostat or Sediment. The dip tube probably disintigrated. The dip tub sends cold water to the bottom of the tank for heating when its heated it rises to the top of the tank. Its possible that the dip tube broke of and now you have cold water mixing with the hot water on top.
The water in the central heating system needs to be at a certain pressure in order for the boiler to work properly and safely. There is a pressure sensor inside the boiler, and if the pressure is too low, it will switch off the boiler to stop it working without enough water and overheating.